What I would suggest is that you go to a nursery that sells and handles bonsai and tools for them. They generally sell a putty for wounds ( comes in a jar or tube),one putty is brown the other is O.D. green. I have used this on all my bonsai's for years. When I remove branches, down to the trunk. You may have to scrap out wound area. Then fill the whole area with putty. In a few years it will callus over. Go to the library or book store. Look a bonsai books. The better books show you how to do this. Or it may be on the net. Or go to ebay. Type in Japanese cut paste.

Sue
Why not root the damaged cuttings horizontally with the wood totally covered so only the tip of the new shoot shows above the rooting medium? Once the roots grow below and the shoot above the rooting medium, the damaged wood should not be causing any problem,

Sue, when one tries to air layer plants, a recommendation is to scar or wound, the area from which one wishes roots to grow. I suspect that the damage that you describe might work to encourage rooting rather than injure the cutting too much.

John.

I have rooted one-node cuttings just to see if I could. They grew just as well as the longer ones. Yours look like they are growing both roots and tops, so hopefully they'll grow OK.

Once your cuttings reach a foot or so, I would be tempted to plant them a little deeper so that a couple of nodes are covered by soil. That would give a chance to root from the sides of the new plant.